Reducing the negative human-health impacts of bioenergy
crop emissions through region-specific crop selection
The MIT Faculty has made this article openly available. Please share
how this access benefits you. Your story matters.
Citation
Porter, William C, Todd N Rosenstiel, Alex Guenther, JeanFrancois Lamarque, and Kelley Barsanti. “Reducing the Negative
Human-Health Impacts of Bioenergy Crop Emissions through
Region-Specific Crop Selection.” Environmental Research
Letters 10, no. 5 (May 1, 2015): 054004. © 2015 IOP Publishing
Ltd
As Published
http://dx.doi.org/10.1088/1748-9326/10/5/054004
Publisher
IOP Publishing
Version
Final published version
Accessed
Fri May 27 00:04:46 EDT 2016
Citable Link
http://hdl.handle.net/1721.1/98376
Terms of Use
Creative Commons Attribution
Detailed Terms
http://creativecommons.org/licenses/by/3.0/
Home
Search
Collections
Journals
About
Contact us
My IOPscience
Reducing the negative human-health impacts of bioenergy crop emissions through regionspecific crop selection
This content has been downloaded from IOPscience. Please scroll down to see the full text.
2015 Environ. Res. Lett. 10 054004
(http://iopscience.iop.org/1748-9326/10/5/054004)
View the table of contents for this issue, or go to the journal homepage for more
Download details:
IP Address: 18.51.1.3
This content was downloaded on 18/08/2015 at 15:05
Please note that terms and conditions apply.
Environ. Res. Lett. 10 (2015) 054004
doi:10.1088/1748-9326/10/5/054004
LETTER
OPEN ACCESS
Reducing the negative human-health impacts of bioenergy crop
emissions through region-specific crop selection
RECEIVED
17 December 2014
REVISED
16 March 2015
William C Porter1,4, Todd N Rosenstiel1, Alex Guenther2, Jean-Francois Lamarque3 and Kelley Barsanti1
1
2
ACCEPTED FOR PUBLICATION
3
31 March 2015
4
PUBLISHED
6 May 2015
Portland State University, Portland, OR 97201, USA
Pacific Northwest National Laboratory, Richland, WA 99354, USA
National Center for Atmospheric Research, Boulder, CO 80305, USA
Current address: Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
E-mail: wporter@mit.edu
Keywords: bioenergy, air quality, climate change
Content from this work
may be used under the
terms of the Creative
Commons Attribution 3.0
licence.
Any further distribution of
this work must maintain
attribution to the
author(s) and the title of
the work, journal citation
and DOI.
Supplementary material for this article is available online
Abstract
An expected global increase in bioenergy-crop cultivation as an alternative to fossil fuels will have
consequences on both global climate and local air quality through changes in biogenic emissions of
volatile organic compounds (VOCs). While greenhouse gas emissions may be reduced through the
substitution of next-generation bioenergy crops such as eucalyptus, giant reed, and switchgrass for
fossil fuels, the choice of species has important ramifications for human health, potentially reducing
the benefits of conversion due to increases in ozone (O3) and fine particulate matter (PM2.5) levels as a
result of large changes in biogenic emissions. Using the Community Earth System Model we simulate
the conversion of marginal and underutilized croplands worldwide to bioenergy crops under varying
future anthropogenic emissions scenarios. A conservative global replacement using high VOCemitting crop profiles leads to modeled population-weighted O3 increases of 5–27 ppb in India,
1–9 ppb in China, and 1–6 ppb in the United States, with peak PM2.5 increases of up to 2 μg m−3. We
present a metric for the regional evaluation of candidate bioenergy crops, as well as results for the
application of this metric to four representative emissions profiles using four replacement scales
(10–100% maximum estimated available land). Finally, we assess the total health and climate impacts
of biogenic emissions, finding that the negative consequences of using high-emitting crops could
exceed 50% of the positive benefits of reduced fossil fuel emissions in value.
1. Introduction
As bioenergy crops continue to replace both existing
agricultural crops and natural landscapes, the choice
of crop species will become increasingly important
given their likely impacts on air quality and climate.
The use of crops such as poplar, eucalyptus, and
switchgrass as bioenergy feedstocks has increased
globally over the past decade, and while ongoing
adoption trends are highly dependent on both economic outcomes and policy decisions, significant
increases are expected to continue (Energy Information Administration 2013). The large scale land-use
changes associated with bioenergy production will
have consequences on many aspects of environmental
and human health, including food supply, watershed
cleanliness, soil quality, and ecological diversity (e.g.
© 2015 IOP Publishing Ltd
Service 2007, Dominguez-Faus et al 2009, Ditomaso
et al 2010, Pedroli et al 2013). In some cases, the
environmental costs associated with bioenergy production and consumption have been estimated to
outweigh the benefits of reduced fossil fuel combustion completely (Hill et al 2009, Tessum et al 2014). In
addition to these concerns, many of the most popular
candidates for bioenergy crop feedstocks are highemitters of isoprene, monoterpenes, and other biogenic volatile organic compounds (BVOCs), precursors of surface-level ozone (O3) and fine particulate
matter (PM2.5). Recent observational and modeling
studies of existing bioenergy crop plantations have
highlighted the importance of examining ambient
chemical and climatological conditions, along with
crop emission profiles, when assessing the potential
for large-scale cultivation to effect negative air quality
Environ. Res. Lett. 10 (2015) 054004
W C Porter et al
consequences in any given area (Hewitt et al 2009,
Porter et al 2012). Thus far, however, strategies to
inform regional energy crop selection and limit the
negative impacts of bioenergy cultivation on air quality
and human health have not been adequately
addressed.
With a global single-year death toll of seven million, air pollution has now been identified as the most
significant environmental risk to human health
(WHO 2014). Over half of the total estimated air pollution related deaths are linked to outdoor exposure,
particularly to elevated levels of O3 and PM2.5 (Brauer
et al 2012). These pollutants largely are secondary,
forming in situ as a result of chemical reactions involving both naturally and anthropogenically emitted
precursors (Sillman 1999, de Gouw and Jimenez 2009), making effective control of their ambient
concentrations particularly challenging. For both O3
and PM2.5, fluxes of BVOCs can play a crucial role in
determining peak daily pollutant concentrations.
While all plants emit BVOCs to some extent, there is
enormous variability in the magnitude of emission
rates between different plant species (Guenther
et al 1995). Thus, large-scale landscape-level changes
in the type and quantity of plants can have profound
consequences on regional air quality by affecting the
rates of BVOC emissions, and therefore rates of O3
and PM2.5 formation (Wiedinmyer et al 2006, Ashworth et al 2012).
While recent work has examined the air quality
consequences of both theoretical and observed landuse changes driven by bioenergy crop cultivation (Porter et al 2012, Ashworth et al 2013), a global study
comparing targeted likely bioenergy crop emission
profiles has not yet been performed. This comparison
is important, since the differences between the highest
and lowest emitting candidate crops are large: eucalyptus and other woody energy crops rank among the
highest of known BVOC emitters (Guenther
et al 1994, Street et al 1997, Padhy and Varshney 2005,
Hewitt et al 1990, Winters et al 2009, Owen 2001),
while rapidly growing cellulosic alternatives such as
switchgrass (Panicum sp.) and Miscanthus (Miscanthus x Giganteus) are among the lowest (Graus
et al 2011, Eller et al 2011). Since the conversion of
existing fossil-fuel based energy sources to these modern bioenergy cropping systems will presumably be
driven by climate and air quality concerns, choosing
feedstocks that do not undermine these efforts
through drastic changes in biogenic emissions will be
critical. As modern bioenergy methods continue to be
developed and applied, the regional selection of feedstock crop will naturally be based on a number of agronomic criteria, including growth rates, hardiness, ease
of cultivation and harvesting, and suitability for efficient conversion to energy. It is the purpose of this
paper to assess whether biogenic emissions must also
be added to emerging feedstock crop-selection criteria
in areas demonstrating high air quality sensitivities.
2
2. Methodology
In this work, the air quality and climatic impacts of
increased biogenic emissions due to a global transition
to bioenergy crop cultivation are examined, and
considerations for reducing these impacts are proposed and evaluated. To compare these impacts, we
model the climate and air quality consequences of
large-scale conversion of underutilized land to bioenergy crop cultivation using the NCAR chemistry
climate model Community Earth System Model
(CESM) 1.1, including version 4 of the Community
Atmosphere Model (Lamarque et al 2012, Neale et al
2013; additional model and crop replacement details
available in supplementary data available at stacks.iop.
org/ERL/10/054004/mmedia). We use three characteristic replacement crop emission profiles representing a range of emission types: trace isoprene emissions
(LOW case), high isoprene emissions (ISO case), and
high isoprene and monoterpene emissions (ISO + MT
case). We also generate a fourth case using an average
of all three emission types to represent an intermediate
emissions scenario (MIXED). We then use each of
these four profiles to simulate varying degrees of landuse change in areas identified as underutilized (Cai
et al 2010) under both current and projected future
anthropogenic emissions scenarios (Meinshausen
et al 2011), and compare them to base cases using nonemitting land rather than a replacement crop.
We run a total of three base cases and 48 replacement cases (table 1), representing a wide range of total
replaced area (143–1430 Mha) and emissions profiles
(low to high BVOC emitters) using both current and
projected anthropogenic emissions and ambient temperatures. Projections of future total biomass energy
production potentials are highly variable, mostly due
to uncertainties in quantifying land availability and
likely crop yields (Berndes et al 2003). For much of this
study, the ‘Moderate’ replacement scale, representing
25% of the full potential area, or around 277 Mha
(supplementary table 1 available at stacks.iop.org/
ERL/10/054004/mmedia), is examined in detail.
Recent literature estimates the area of global abandoned agricultural land at approximately 400 Mha
(Campbell et al 2008), making the Moderate case a
relatively conservative estimate. We analyze the global
model results for six regions with the largest estimates
of potentially available land area: Africa, China, Europe, India, South America and the United States. Estimates of net energy gain (NEG) per hectare of energy
crop vary widely, even within individual species (Collura et al 2006, Lewandowski and Schmidt 2006,
Angelini et al 2009, Schmer et al 2009, 2014, US
Department of Energy 2011), but conservative NEG
values suggest that land-use conversion in the most
aggressive scenarios could generate approximately
10% of current global electricity production.
In addition to comparing pollutant changes
between crop profiles and anthropogenic emissions
Environ. Res. Lett. 10 (2015) 054004
W C Porter et al
Table 1. Settings used for all 46 simulated cases (above), and changes to population-weighted NOx resulting from modified anthropogenic
emissions (below).
Crop emission types (4 + base)
Replacement scales (4)
Anthropogenic emissions (3)
Base
ISO + MT
ISO
LOW
MIXED (average of above profiles)
none
100%, 50%, 25%, 10%
100%, 50%, 25%, 10%
100%, 50%, 25%, 10%
100%, 50%, 25%, 10%
currenta, RCP4.5b, RCP8.5b
currenta, RCP4.5b, RCP8.5b
currenta, RCP4.5b, RCP8.5b
currenta, RCP4.5b, RCP8.5b
currenta, RCP4.5b, RCP8.5b
Region
RCP4.5 NOx
RCP8.5 NOx
−5%
+3%
−41%
+47%
−17%
−49%
Africa
China
Europe
India
South America
United States
a
b
−3%
+59%
−35%
+53%
−13%
−42%
Default CESM emissions via POET, REAS, GFED2.
Lamarque et al (2011).
scenarios, we perform an analysis of human-health
impacts of alternative cropping scenarios. Using
population distribution data and concentration
response estimates we estimate the number of lives
affected by degraded air quality and assess a health cost
on a regional basis (Jerrett et al 2009, Krewski et al
2009, Anenberg et al 2010). We then weight changes in
O3 and PM2.5 by population density and normalize
results by replacement scale to generate an aggregate
‘energy crop air quality score’ (ECAQS) for each crop
and region. Following the examination of urban tree
selection and air quality effects presented in Donovan
et al 2005, the ECAQS score can be understood as the
population-weighted average change in air quality
(measured relative to WHO standards for O3 and
PM2.5) per 10 Mha of energy crop planted in that
region, allowing for a normalized measure of AQ sensitivity to variation in crop type and regional abundance. An ECAQS score of negative ten, for example,
indicates that the population will see an average
increase in pollutant concentrations equivalent to
10% of their respective standards.
3. Results and discussion
3.1. Air quality impacts
Our model results show highly non-linear, regionspecific air quality impacts of bioenergy crop selection
(figure 1), demonstrating the need for regional crop
selections taking local sensitivities into account. Simulated O3 generally increase for all three high-emitting
crop types, with especially large summertime effects
predicted in the following regions: India (average
increases of 5–27 ppb population-weighted summertime O3 for the Moderate replacement cases), China
(1–9 ppb O3), and the United States (1–6 ppb O3).
However, changes in O3 levels are low or even negative
in areas exhibiting already low NOx/volatile organic
3
compound (VOC) ratios, such as South America,
where changes in O3 range from −1 ppb in the summer
to +1 ppb in the winter for the Moderate replacement
scale ISO and ISO + MT cases, respectively. Secondary
organic aerosol formation in all regions is primarily
driven by monoterpene emissions, characteristic of
the ISO + MT and MIXED cases. ISO replacement
cases show some PM2.5 response, but at much reduced
levels, while the LOW cases show negligible impacts
on PM2.5 concentrations. Unlike O3, PM2.5 levels
consistently increase with greater crop replacement
area. PM2.5 levels also show much less sensitivity to
future changes in climate and emissions. In China and
India maximum population-weighted changes in
PM2.5 approach 2 μg m−3 for the ISO + MT case.
Since the health risks associated with PM2.5 exceed
those of tropospheric O3 relative to the magnitudes of
changes evident in this study, the high monoterpene
emissions of the ISO + MT cases result in the greatest
estimated health costs among the four crop types, with
over 410 000 premature deaths worldwide associated
with the Moderate replacement level (see supplementary data for more details on mortality estimate calculations (available at stacks.iop.org/ERL/10/054004/
mmedia)). Using the reduced emissions of the ISOonly profile leads to 328 000 premature deaths, while
conversion of land using LOW emissions shows only
very small changes in O3 and PM2.5, and therefore negligible increases in premature deaths. Notably, mixing
the three crop types (MIXED) proves to be more detrimental than might be expected, with mortality increases almost identical to those of the ISO case
worldwide, and greater than the average of the three
emissions cases for each individual region. This may
be related to nonlinearities in pollutant formation,
and therefore in the resulting changes in mortality
estimates. The scale of estimated land availability and
dense population distributions in India, Africa, and
Environ. Res. Lett. 10 (2015) 054004
W C Porter et al
Figure 1. Base regional population-weighted pollutant levels (in black) and changes to those levels with bioenergy crop replacement
(in color), averaged over all emissions scenarios (current, RCP4.5, and RCP8.5) using the Moderate replacement scale. Shaded regions
indicate the full range of model output over all emissions scenarios. O3 levels are calculated using maximum 8 h averages, while PM2.5
concentrations represent daily averages. Note the different y-axis scales.
China makes health effects in those areas the most sensitive to increased VOC emissions from bioenergy
crops. These areas, already among the most affected by
outdoor air pollution (Cohen et al 2005), account for
approximately 70% of the increased mortality
worldwide.
4
The extent to which air quality concerns should be
taken into account in the selection of bioenergy crops
on a regional basis can be evaluated quantitatively by
comparing differences in the ECAQS for each crop
and region (table 2). Total scores for ISO + MT emissions at the Moderate replacement scale range from
Environ. Res. Lett. 10 (2015) 054004
W C Porter et al
Table 2. Average Energy Crop Air Quality Scores by region and pollutant for the Moderate replacement scale cases. ECAQS represents
change in population-weighted, standard-normalized air quality per 10 Mha of energy crop planted. Peak column represents the maximum
monthly average change by crop and region.
Africa
ISO + MT
ISO
LOW
MIX
China
O3
PM2.5
Total
−0.6
−0.6
0.0
−0.5
−1.0
−0.6
0.0
−0.5
−1.6
−1.2
0.0
−1.0
Peak
−2.2
−1.7
0.0
−1.3
India
ISO + MT
ISO
LOW
MIX
Europe
O3
PM2.5
Total
Peak
O3
PM2.5
Total
Peak
−1.8
−1.9
0.0
−1.8
−2.1
−1.1
0.0
−1.2
−3.8
−3.0
0.0
−3.0
−6.1
−4.7
−0.1
−4.8
−0.8
−0.8
0.0
−0.6
−0.6
−0.5
0.0
−0.4
−1.4
−1.4
0.0
−1.0
−3.1
−3.0
0.0
−2.3
South America
United States
O3
PM2.5
Total
Peak
O3
PM2.5
Total
Peak
O3
PM2.5
Total
Peak
−7.5
−7.6
0.0
−6.7
−6.9
−3.8
−0.1
−3.6
−14.4
−11.4
−0.1
−10.3
−23.1
−18.3
−0.2
−16.4
−0.1
−0.1
0.0
−0.1
−0.8
−0.6
0.0
−0.5
−0.9
−0.7
0.0
−0.5
−1.2
−1.0
0.0
−0.8
−1.2
−1.3
0.0
−1.1
−1.7
−1.0
0.0
−1.0
−2.9
−2.3
0.0
−2.1
−5.2
−4.2
0.0
−3.7
Figure 2. Air quality impacts of high-emitting ISO + MT case (map) with relative health benefits of lower-emitting crops, by region
(inset figures). Map color shows the sum of changes to O3 and PM2.5 (normalized by their respective WHO standards and therefore
unitless) for the ISO + MT case using the Moderate replacement scale. Inset bar plots show mean deaths prevented (in thousands) per
GJ × 106 energy produced, by region, for lower-emitting options versus the ISO + MT case.
−0.9 in South America, where low NOx levels and a
fairly disperse human population keeps health impacts
modest; to −14.4 in India, where the density of human
population and replacement areas make the air quality
consequences of crop selection an especially important factor.
The potential increase in productivity of higheremitting crops when compared to low-emitting crops
such as miscanthus or switchgrass may be justifiable
5
when the population-weighted impacts of the higher
emissions are relatively low, as in Africa and South
America. On the other hand, the larger impacts shown
in the other four regions suggest that finding lowemitting solutions may be crucial for any region-wide
implementation of a bioenergy cultivation strategy.
Furthermore, comparing the ISO + MT and ISO cases
highlights the relative importance of monoterpene
and isoprene emissions in each region. While PM2.5
Environ. Res. Lett. 10 (2015) 054004
W C Porter et al
impacts are larger for the ISO + MT case in all regions,
in some areas the health effects of increased O3 may
outweigh those of PM2.5, reducing the difference
between isoprene-only emitters such as giant reed and
monoterpene emitters such as eucalyptus. The combined health benefits of using lower-emitting crops for
bioenergy production is evident in figure 2, where
summed impacts of O3 and PM2.5 changes for the
ISO + MT case are shown in red, with regional benefits
of lower-emitting options (in deaths prevented per
energy produced) shown as inset bar plots.
3.2. Climatic impacts
In addition to local air quality effects, a worldwide shift
towards high VOC-emitting bioenergy crop cultivation would have global climatological impacts, including possible changes to methane (CH4) lifetimes and
the aerosol radiative effect. The highest crop emission
case (100% ISO + MT replacement) results in globally
averaged OH levels reduced by approximately 20%
compared to the base simulation after correcting for
estimated HOx recycling impacts (Lelieveld et al 2008,
Petters et al 2009, da Silva et al 2010; see supplementary
data available at stacks.iop.org/ERL/10/054004/
mmedia). While CH4 emissions worldwide are projected to decline over the 21st century under all but the
highest emitting scenarios (Meinshausen et al 2011), a
reduction in the OH concentration of this magnitude
as a result of bioenergy crop emissions would increase
average CH4 lifetimes by up to two years, leading to
higher concentrations and a corresponding increase in
CH4-induced warming. Although reduced replacement areas and lower-emitting crops would have a
lesser impact on CH4, the inclusion of even small
impacts on CH4 may be important additions to the
overall cost-benefit calculations associated with bioenergy crop selection. Based on OH reductions in the
simulations for current atmospheric conditions,
changes to the CH4 radiative effect could be as high as
0.19 W m−2 in the Maximum ISO + MT case. Such
values would represent over 1/3 of the total modern
CH4 radiative forcing estimates, highlighting the
potentially significant impact that large-scale increases
in high VOC-emitting bioenergy crops can have on
Earth’s climate system. Peak changes for the ISO and
MIXED cases are predicted to be less than that, at 0.13
and 0.12 W m−2 respectively, with reduced-scale
replacement schemes scaling down nearly linearly.
The increase in total organic aerosol burden would
have complex effects on the net energy budget of the
atmosphere, affecting not only incoming radiation
directly, but also a variety of cloud properties such as
albedo and lifetime. Greater levels of PM2.5 are predicted for most replacement scenarios, contributing
an overall cooling effect. Taken together, the increased
CH4 lifetime and aerosol burden resulting from
enhanced BVOC emissions would be expected to have
competing effects on radiative forcing, with the CH4
6
Figure 3. Climate and human health costs related to biogenic
emissions for simulated emissions types. All impacts are
normalized to equivalent CO2 emissions (CO2e) and compared to estimated benefit of an associated reduction in coal
emissions. Error bars reflect uncertainties in crop yield and
variability in modeled output across the full set of simulated
scales and emissions scenarios.
effect greater by a factor of approximately five in these
simulations. Since the reduction of radiative forcing
from greenhouse emissions is one of the main goals
driving the present move towards bioenergy development and expansion, taking such BVOC related feedbacks into account will be important when assessing
bioenergy crop selection and expansion from a global
perspective.
3.3. Total costs
Finally, we perform economic assessments of climatic
and human-health impacts using estimates for the
social cost of carbon, and value of a statistical life.
Literature values for both of these costs vary greatly,
depending heavily upon future economic and atmospheric assumptions. For this work we use conservative, low-end estimates of $21 per ton CO2
(IAWG 2010) and $1 million per statistical life (Viscusi
and Aldy 2003). We then convert the climatic and
human health costs associated with each modeled crop
type into equivalent CO2 (CO2e) and compare them to
estimated benefits of coal combustion reductions
(Burnham et al 2012), to produce a comparison of
costs and benefits for each crop emission type
(figure 3). Costs associated with increased CH4 (minus
the cooling effects of increased organic aerosol) are
approximately 8–10% of the expected value of reduced
fossil fuel emissions for ISO + MT, ISO, and MIXED
emission cases, and negligible for the LOW case.
Globally summed health costs are larger, totaling
24–45% of the dollar value of reduced fossil fuel
emissions for the high BVOC-emitting cases. These
costs make the reduction in negative climate and
human health impacts associated with a low-emitting
bioenergy crop like switchgrass especially attractive.
Under these assumptions, high-emitting crops would
dramatically mitigate any net benefits of greenhouse
gas emission reductions, primarily through impacts
on human health.
Environ. Res. Lett. 10 (2015) 054004
W C Porter et al
3.4. Land-use change assumptions and uncertainties
In simplifying and evaluating the impacts of largescale global trends as we have done here, important
assumptions must be made. For one, we use a single
land-availability map to determine replacement areas
worldwide, scaling each grid cell down uniformly for
reduced area cases. In practice, bioenergy crops will
probably not be distributed in this manner, and are
more likely to be clustered in dense areas around
processing facilities. This difference in distribution
and density would likely affect the resulting air quality
impacts. Likewise, land-use change consequences will
be highly dependent on the original land being
replaced, a sensitivity that remains unexplored in our
study.
While we have chosen values representative of
typical candidate crops, the specific phenology, yields,
and cultivation needs of selected feedstocks will also
vary greatly between species and regions. For this reason, the comparisons presented here should be considered emblematic of the wide-ranging bioenergy
crop options available, rather than evaluations of specific crops.
4. Summary
As alternatives to fossil fuels are increasingly adopted,
it will be crucial to do so in ways that seek to maximize
carbon reduction while also minimizing associated
negative consequences. The results of this study
suggest that, while cultivation of high productivity
bioenergy crops may offer an attractive option for
biomass-based energy production in many areas of the
world, air quality and climate impacts of crop emissions must also be considered alongside other concerns such as water availability, biodiversity, and food
security. In terms of biogenic emissions, using a lowemitting crop such as switchgrass or Miscanthus
rather than a higher-emitting alternative could maximize any expected environmental benefits of reduced
fossil fuel use. However, the possibility of lower
potential yields of these crops compared to higher
VOC-emitting options may affect the final costbenefit analysis of any proposed bioenergy development. By evaluating the local and global consequences
of crop selection on a case-by-case basis, including
calculation of ECAQS values for candidate crops as
performed here, these considerations can help to
further inform energy policy and maximize the
benefits of alternative energy production while minimizing the negative impacts of bioenergy crop cultivation on air quality, human health, and climate.
References
Anenberg S C, Horowitz L W, Tong D Q and West J J 2010 An
estimate of the global burden of anthropogenic ozone and
fine particulate matter on premature human mortality using
atmospheric modeling Environ. Health Perspect. 118 1189–95
7
Angelini L G, Ceccarini L, Nassi o Di Nasso N and Bonari E 2009
Comparison of arundo donax L. and miscanthus x giganteus
in a long-term field experiment in central Italy: analysis of
productive characteristics and energy balance Biomass
Bioenergy 33 635–43
Ashworth K, Folberth G, Hewitt C N and Wild O 2012 Impacts of
near-future cultivation of biofuel feedstocks on atmospheric
composition and local air quality Atmos. Chem. Phys. 12
919–39
Ashworth K, Wild O and Hewitt C N 2013 Impacts of biofuel
cultivation on mortality and crop yields Nat. Clim. Change 3
492–6
Bell M L, Peng R D and Dominici F 2006 The exposure–response
curve for ozone and risk of mortality and the adequacy of
current ozone regulations Environ. Health Perspect. 114
532–6
Berndes G, Hoogwijk M and van den Broek R 2003 The
contribution of biomass in the future global energy supply: a
review of 17 studies Biomass Bioenergy 25 1–28
Brauer M et al 2012 Exposure assessment for estimation of the
global burden of disease attributable to outdoor air pollution
Environ. Sci. Technol. 46 652–60
Burnham A, Han J, Clark C E, Wang M, Dunn J B and
Palou-Rivera I 2012 Life-cycle greenhouse gas emissions of
shale gas, natural gas, coal, and petroleum Environ. Sci.
Technol. 46 619–27
Cai X, Zhang X and Wang D 2010 Land availability for biofuel
production Environ. Sci. Technol. 45 334–9
Campbell J E, Lobell D B, Genova R C and Field C B 2008 The global
potential of bioenergy on abandoned agriculture lands
Environ. Sci. Technol. 42 5791–4
Cohen A J et al 2005 The global burden of disease due to outdoor air
pollution J. Toxicol. Environ. Health A 68 1301–7
Collura S, Azambre B, Finqueneisel G, Zimny T and Victor Weber J
2006 Miscanthus x giganteus straw and pellets as sustainable
fuels Environ. Chem. Lett. 4 75–8
Da Silva G, Graham C and Wang Z-F 2010 Unimolecular βhydroxyperoxy radical decomposition with OH recycling in
the photochemical oxidation of isoprene Environ. Sci.
Technol. 44 250–6
De Gouw J and Jimenez J L 2009 Organic aerosols in the earth’s
atmosphere Environ. Sci. Technol. 43 7614–8
Ditomaso J M, Reaser J K, Dionigi C P, Doering O C, Chilton E,
Schardt J D and Barney J N 2010 Biofuel vs bioinvasion:
seeding policy priorities Env. Sci Technol. 44 6906–10
Dominguez-Faus R, Powers S E, Burken J G and Alvarez P J 2009
The water footprint of biofuels: a drink or drive issue? Env. Sci
Technol. 43 3005–10
Donovan R G, Stewart H E, Owen S M, MacKenzie A R and
Hewitt C N 2005 Development and application of an urban
tree air quality score for photochemical pollution episodes
using the birmingham, united kingdom, area as a case study
Environ. Sci. Technol. 39 6730–8
Eller A S D, Sekimoto K, Gilman J B, Kuster W C, de Gouw J A,
Monson R K, Graus M, Crespo E, Warneke C and Fall R
2011 Volatile organic compound emissions from
switchgrass cultivars used as biofuel crops Atmos. Environ. 45
3333–7
Energy Information Administration 2013 Annual Energy Outlook
2013: Early Release Overview (Washington, DC: US Energy
Information Adminstration)
Graus M, Eller A S D, Fall R, Yuan B, Qian Y, Westra P,
de Gouw J and Warneke C 2013 Biosphere-atmosphere
exchange of volatile organic compounds over C4 biofuel
crops Atmos. Environ. 66 161–8
Guenther A et al 1995 A global model of natural volatile organic
compound emissions J. Geophys. Res. 100 8873–92
Guenther A, Zimmerman P and Wildermuth M 1994 Natural
volatile organic compound emission rate estimates for US
woodland landscapes Atmos. Environ. 28 1197–210
Hewitt C N, Monson R and Fall R 1990 Isoprene emissions from the
grass arundo donax L. Are not linked to photorespiration
Plant Sci. 66 139–44
Environ. Res. Lett. 10 (2015) 054004
W C Porter et al
Hewitt C N et al 2009 Nitrogen management is essential to prevent
tropical oil palm plantations from causing ground-level
ozone pollution Proc. Natl Acad. Sci. USA 106 18447–51
Hill J, Polasky S, Nelson E, Tilman D, Huo H, Ludwig L, Neumann J,
Zheng H and Bonta D 2009 Climate change and health costs
of air emissions from biofuels and gasoline Proc. Natl Acad.
Sci. 106 2077–82
IAWG U 2010 Technical support document: social cost of carbon for
regulatory impact analysis under executive order 12866
(Interagency Working Group on Social Cost Carbon)
(Washington, DC: United States Government)
Jerrett M, Burnett R T, Pope C A, Ito K, Thurston G, Krewski D,
Shi Y, Calle E and Thun M 2009 Long-term ozone exposure
and mortality New England J. Med. 360 1085–95
Krewski D 2009 Evaluating the effects of ambient air pollution on
life expectancy New England J. Med. 360 413–5
Lamarque J-F, Kyle G P, Meinshausen M, Riahi K, Smith S J,
Vuuren D P, van, Conley A J and Vitt F 2011 Global and
regional evolution of short-lived radiatively-active gases and
aerosols in the representative concentration pathways Clim.
Change 109 191–212
Lamarque J-F et al 2012 CAM-chem: description and evaluation of
interactive atmospheric chemistry in the community earth
system model Geosci. Model Dev. 5 369–411
Lelieveld J et al 2008 Atmospheric oxidation capacity sustained by a
tropical forest Nature 452 737–40
Lewandowski I and Schmidt U 2006 Nitrogen, energy and land use
efficiencies of miscanthus, reed canary grass and triticale as
determined by the boundary line approach Agric. Ecosyst.
Environ. 112 335–46
Meinshausen M, Smith S J, Calvin K, Daniel J S, Kainuma M L T,
Lamarque J F, Matsumoto K, Montzka S A, Raper S C B and
Riahi K 2011 The RCP greenhouse gas concentrations and
their extensions from 1765 to 2300 Clim. Change 109 213–41
Neale R B, Richter J, Park S, Lauritzen P H, Vavrus S J, Rasch P J and
Zhang M 2013 The mean climate of the community
atmosphere model (CAM4) in forced SST and fully coupled
experiments J. Clim. 26 5150–68
Owen S 2001 Volatile organic compounds (VOCs) emitted from 40
mediterranean plant species: VOC speciation and
extrapolation to habitat scale Atmos. Environ. 35 5393–409
Padhy P K and Varshney C K 2005 Isoprene emission from tropical
tree species Environ. Pollut. 135 101–9 (Barking Essex 1987)
Pedroli B, Elbersen B, Frederiksen P, Grandin U, Heikkilä R,
Krogh P H, Izakovičová Z, Johansen A, Meiresonne L and
Spijker J 2013 Is energy cropping in Europe compatible with
biodiversity?—opportunities and threats to biodiversity from
land-based production of biomass for bioenergy purposes
Biomass Bioenergy 55 73–86
8
Peeters J, Nguyen T L and Vereecken L 2009 HOx radical
regeneration in the oxidation of isoprene Phys. Chem. Chem.
Phys. 11 5935–9
Pope C A III, Burnett R T, Thun M J, Calle E E, Krewski D, Ito K and
Thurston G D 2002 Lung cancer, cardiopulmonary mortality,
and long-term exposure to fine particulate air pollution
J. Am. Med. Assoc. 287 1132–41
Porter W C, Barsanti K C, Baughman E C and Rosenstiel T N 2012
Considering the air quality impacts of bioenergy crop
production: a case study involving arundo donax Environ. Sci.
Technol. 46 9777–84
Schmer M R, Vogel K P, Mitchell R B and Perrin R K 2008 Net
energy of cellulosic ethanol from switchgrass Proc. Natl Acad.
Sci. USA 105 464–9
Schmer M R, Vogel K P, Varvel G E, Follett R F, Mitchell R B and
Jin V L 2014 Energy potential and greenhouse gas emissions
from bioenergy cropping systems on marginally productive
cropland PLoS ONE 9 1–8
Service R F 2007 Biofuel researchers prepare to reap a new harvest
Science 315 1488–91
Sillman S 1999 The relation between ozone, NOx and hydrocarbons
in urban and polluted rural environments Atmos. Environ. 33
1821–45
Street R A, Hewitt C N and Mennicken S 1997 Isoprene and
monoterpene emissions from a eucalyptus plantation in
Portugal J. Geophys. Res. 102 15875–15
Tessum C W, Hill J D and Marshall J D 2014 Life cycle air quality
impacts of conventional and alternative light-duty
transportation in the United States Proc. Natl Acad. Sci.USA
111 18490–5
US Department of Energy 2011 US Billion-Ton Update: Biomass
Supply for a Bioenergy and Bioproducts Industry (Oak Ridge,
TN: Oak Ridge National Laboratory, US Department of
Energy)
Viscusi W K and Aldy J E 2003 The value of a statistical life: a critical
review of market estimates throughout the world J. Risk
Uncertain. 27 5–76
Wiedinmyer C, Tie X, Guenther A, Neilson R and Granier C 2006
Future changes in biogenic isoprene emissions: how might
they affect regional and global atmospheric chemistry? Earth
Interact. 10 1–19
Winters A J, Adams M A, Bleby T M, Rennenberg H, Steigner D,
Steinbrecher R and Kreuzwieser J 2009 Emissions of
isoprene, monoterpene and short-chained carbonyl
compounds from eucalyptus spp. in southern Australia
Atmos. Environ. 43 3035–43
World Health Organisation 2014 7 million premature deaths
annually linked to air pollution Online report (www.who.int/
mediacentre/news/releases/2014/air-pollution/en/)